Brush-holder.



WALKER. BRUSH HOLDER.

APPLICATION FILED JAN. 17. 1912.

1,166,161. Patented D60.28,1915.

WITNESSES: INVENTOR W M W ATTORNEY UNITED STATES PATENT OFFICE.

MILES WALKER, OF HALE, ENGLAND, ASSIGNOR TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

BRUSH-HOLDER.

Application filed January 17, 1912.

To all whom it may concern:

Be it known that I, MILES WALKER, a subject of the King of Great Britain, and a resident of Hale, in the county of Chester, England, have invented a new and useful Improvement in Brush-Holders, of which the following is a specification.

. My invention relates to brush holders for dynamo electric machines, and it has for its main object to provide an improved device of the class indicated, by means of which the brushes shall be maintained at all times at the same angle with the cooperating ro tatable member.

In brush holders, as at present constructed, it is possible for a brush to move through a small angle and so to change its inclination to the commutator cylinder. Further more, in a brush holder of the box type, in which the brush slides between the parallel sides of a metal box, it is found that, if a certain amount of play is not allowed between the brush and the box, the brush will become jammed when it expands with heat or when dust or dirt collects between it and the box. It is also found that, if the brush fits sufficiently loosely in the box to prevent jamming, it can move through a certain angle, which, though small, prevents it from operating in a perfectly satisfactory manner. In other cases, the brush holders themselves yield a little, as the commutator cylinder rotates, on account of the resiliency of the metal of which they are constructed, and this gives rise to chattering.

According to my present invention, in order to prevent the yielding or springing of the brush holder, the brushes are located directly adjacent to the brush arms, which are made rigid and strong. Each brush arm is provided with a broad flat surface against which the brush is pressed by a spring or springs with such force that it requires a greater turning moment to separate the brush from the brush arm than can possibly be exerted by the frictional resistance occurring between the brush and the commutator. The point of application of the force exerted by the spring is well inside the limits of the broad face against which the brush is pressed, so that the angle which the brush makes with the commutator is main- The pressure of the brush" tained constant.

not to prevent the easy sliding of the brush Specification of Letters Patent.

Patented Dec. 28, 1915.

Serial No. 671,747.

relative to the brush arm, and the latter is preferably so placed with reference to the direction of rotation of the machine that the movement of the commutator cylinder tends to force the brush against the arm. For the purpose of pressing the brush against the surface of the commutator cylinder and feeding it forward as it wears away, a spring is provided to act in a line parallel with the plane surface of the brush. arm and in the center line of the brush, as will be hereinafter more fully explained.

In order that my invention may be clearly understood, it will now be described with reference to the accompanying drawing in which Figure 1 is a front elevation and Fig. 2 a vertical transverse sectional view of a brush holder constructed in accordance therewith. Figs. 3, 4i and 5 are, respectively, enlarged views, in front elevation, in side elevation, partially in section, and in plan of a portion of the device shown in Figs. 1 and 2.

Referring now to the drawings, a brush arm 1, which is made strong and rigid, is provided with a slotted extension 2 through which bolts 9f may project for the purpose of securing it to a rocker-arm or other suitable supporting structure (not shown). The arm 1 is provided with a broad flat surface 3 and with end extensions 4 and 5 to which a front plate 6 is secured by means of screws 7. A plurality of brushes 8 are mounted side-by-side between the surface 8 and the plate 6 and are severally pressed against the surface 3 by springs 9 which are secured to the plate 6 and apply their pressure approximately midway between an edge 10 of the brush arm 1 which is farthest from a commutator cylinder 11 and the edge of the surface 3 which is adjacent thereto.

The commutator cylinder 11, which is shown in dot and dash lines in Fig. 2, may be of any well known construction and preferably rotates in the direction indicated by "the arrow.

' For the purpose of pressing the brushes against the surface of the commutator and feeding them forward as they wear away, each brush is provided with an actuating device 12 which is indicated in outline in Figs. 1 and 2, and is shown in detail in Figs.

4i and 5. The device 12 comprises a tube against the arm is, however, so adjusted as fi 13 having a vertical slot 14 provided with offset notches 15, as shown. The upper end of the tube 13 is closed by a plug 16 which is firmly held in position by a pin 17. The ends of the pin 17 pro ect beyond the tube 13 and into recesses or apertures in a U-shaped clip 18, which is secured by a bolt 19 to the brush arm 1. The tube 13 is thereby pivoted in the clip 18 but is retained in position with center line parallel with the flat face 3 of the brush arm 1 by means of a spring 20 which, however, permits it to move up on its pivot, when desired.

l Vithinthe tube 13 is a tube or sleeve 21, the upper end of which is closed by a plug 22 carrying a pin 23 which projects through the slot 14; and a third tube or sleeve 21 is adapted to slide within the tube or sleeve 21, the lower end of the former being provided with a rounded button 24 between which and the plug 22 is a helical spring 25. Each brush is provided with one of the actuating devices 12, and the axis of each spring 25 is substantially coincident with the center line of the brush with the top of which the button 241- is adapted to engage.

In order to conduct current from the brushes 8 to the brush arm 1, flexible shunts 26 are provided, one end of each shunt being attached to the brush and the other end being secured in a recess 27 in the brush arm by means of a screw 28.

It will be readily understood without further description, that the pin 23 may be caused to engage with any one of the notches 15, so as to adjust the pressure of the springs 25 upon the brushes 8 as said brushes wear away.

When it is desired to remove a brush. 8 or to inspect or clean the tubes or sleeves 21 and 21 containing the spring 25, the device 12 can readily be swung outwardly upon the pivot pin 17 through any desired angle.

The brush holder 1, shown in the drawing, is adapted to receive a plurality of brushes that are disposed side by side, without any intervening partitions, enough clearance being allowed to give an easy sliding lit. This construction permits the brushes 8 to be placed considerably closer together than in the arrangements heretofore employed, and effects a considerable saving in the length of the commutator. More than one spring 25 may be provided for pressing each brush 8 against the commutator cylinder 11 if desired. It will be understood, however that the improved construction may be used with a single brush if desired.

I will be seen that, with the brush holder hereinbefore described, the pressure of the spring 25 is at all times substantially in the direction of the center line of the brush, whether the brush be new or whether it be Worn. There is, therefore, no tendency for the brush to rock or to have a heel and toe motion on the commutator cylinder. The improved construction is furthermore very simple, and permits of the parts being very readily inspected and cleaned.

Modifications in the structural details and in the arrangement and location of parts may, of course, be made without departing from the spirit and scope of my invention.

1 claim as my invention:

1. A brush holder for dynamo-electric machines comprising a supporting arm, a brush slidably associated therewith, a spring to maintain said brush against said arm, a second pivotally supported spring to force said brush forward, and resilient means for maintaining the said pivotally supported spring in operative relation to the said brush.

2. A brush holder for dynamo-electric machines comprising a supporting arm having a broad plane surface, a plurality of brushes associated with said arm, a plurality of springs severally adapted to press said brushes against said plane surface, a plurality of pivotally mounted springs severally adapted to press said brushes forward, and resilient means for maintaining the said pivotally mounted springs in operative relation to the said brushes.

3. A brush holder for dynamo-electric machines comprising a supporting arm having a broad plane surface, a brush slidably associated with said arm, means for pressing said brush against said plane surface, a pivotally mounted and adjustable pressure device acting along the center line of said brush against its outer end, and means for yieldingly maintaining thesaid adjust-- able pressure device in operative relation to the said brush.

4. In a brush holder for dynamo-electric machines, the combination with a ri id supporting arm having a broad plane surface, a plurality of brushes associated with said arm in side-by-side relation, and a plurality of springs severally acting on the tops of the brushes along their center lines, pivotally supported receptacles for said springs, springs adapted to maintain the said receptacles in alinement with the said brushes, and a plurality of springs severally acting against the sides of said brushes for holding said brushes against the plane surface of said supporting arm.

5. In a brush holder for dynamo-electric machines, the combination with a rigid supporting arm and a plurality of brushes, of means for maintaining the said brushes resiliently against the said arm in a side-byside relation, and a plurality of adjustable pressure devices independently pivoted to said arm and adapted to exert pressure against the ends of said brushes.

6. In a brush holder for dynamo-electric machines, the combination with a rigid supporting arm, and a plurality of brushes slidably associated therewith and disposed in side-by-side relation, of a plurality of tubular members pivotally attached to said arm and having notched slots therein, each tubular member having its axis coincident with the center line of one of said brushes, a sleeve located Within said tubular member and adapted to cooperate with said notched slot, a second sleeve located within said first sleeve and adapted to engage the top surface of one of said brushes, and a coil spring disposed within said second sleeve between the upper end of said first sleeve and the lower end of said second sleeve.

In testimony whereof, I have hereunto subscribed my name this third day of J anuary, 1912.

MILES WALKER. Witnesses:

JAS. STEWART BROADFOOT, H. R. KITSON.

Copies 0! this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

